Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue:
Revenue from licensing agreements, grants and other	$ 30,131	$ 23,479	$ 51,128	$ 47,063
Operating expenses:
Research and development	7,238,985	5,839,327	13,531,176	10,469,001
General and administrative	2,063,729	2,143,656	4,752,925	4,379,669
Total operating expenses	9,302,714	7,982,983	18,284,101	14,848,670
Loss from operations	(9,272,583)	(7,959,504)	(18,232,973)	(14,801,607)
Other income (expense):
Change in fair value of warrant liability	988,367	(3,654,470)	641,037	(3,981,094)
Interest income	2,139	1,689	3,533	3,874
Interest expense	(146,267)	(343,224)	(331,623)	(723,712)
Other income (expense), net	(33,370)	(15,226)	107,611	(30,724)
Total other expense, net	810,869	(4,011,231)	420,558	(4,731,656)
Net loss from continuing operations	(8,461,714)	(11,970,735)	(17,812,415)	(19,533,263)
Discontinued operations:
Loss from discontinued operations		(144,489)		(202,217)
Net loss	$ (8,461,714)	$ (12,115,224)	$ (17,812,415)	$ (19,735,480)
Basic and diluted net loss per share:
Basic and diluted net loss per share from continuing operations	$ (0.09)	$ (0.22)	$ (0.22)	$ (0.36)
Basic and diluted net loss per share from discontinued operations	0	0	0	0
Basic and diluted net loss per share	$ (0.09)	$ (0.22)	$ (0.22)	$ (0.36)
Weighted average number of common shares outstanding, basic and diluted	95,190,823	55,711,717	82,277,137	55,529,818